Angular momentum transport and turbulence in laboratory models of Keplerian flows

TL;DR

This study measures angular momentum transport in laboratory Taylor-Couette flows, revealing how turbulence and rotation influence transport rates, which could have implications for astrophysical disk accretion processes.

Contribution

The paper provides a comprehensive analysis of torque measurements across various control parameters, highlighting the dependence on Reynolds and rotation numbers in Keplerian-like flows.

Findings

Torque scales with Reynolds and rotation numbers

Keplerian-like flows achieve about 14% of maximum transport

Estimated accretion rate in disks is around 10^{-3} of maximum

Abstract

We present angular momentum transport (torque) measurements in two recent experimental studies of the turbulent flow between independently rotating cylinders. In addition to these studies, we reanalyze prior torque measurements to expand the range of control parameters for the experimental Taylor-Couette flows. We find that the torque may be described as a product of functions that depend only on the Reynolds number, which describes the turbulent driving intensity, and the rotation number, which characterizes the effects of global rotation. For a given Reynolds number, the global angular momentum transport for Keplerian-like flow profiles is approximately 14% of the maximum achievable transport rate. We estimate that this level of transport would produce an accretion rate of $\dot{M}/\dot{M_0} \sim 10^{-3}$ in astrophysical disks. We argue that this level of transport from hydrodynamics alone could be significant.